As more people become proficient with developing and publishing their own Android apps, they can also take advantage of the ease of communication with Arduino projects for data analysis, remote control and other uses. However as there isn't an Arduino Bluetooth board on the market, a cheaper solution is to make use of a board with a USB host shield. The people at Circuits@Home have thus described how to easily connect an Android phone with bluetooth an an Arduino board with a USB host shield adaptor, USB dongle and a library to make it happen.
If you're looking for an Arduino-compatible board with inbuilt USB host shield, look no further as we have the Freetronics USBDroid board:
Apart from being a fully Arduino Uno-compatible, it has onboard microSD socket and the full USB socket and host-mode controller. As well as the Bluetooth application described above, this is the ideal platform for developing peripherals or projects based around Android devices with ADK (Android Developer Kit) functionality, but without requiring a USB host controller shield stacked onto an Arduino. For more information and to order, visit the product page here.